1. Field of the Invention
The present invention relates to cover folders for permanently binding sheets of paper and methods for permanently binding sheets of paper to a cover folder or binder spline.
2. Description of the Prior Art
Cover folders for holding sheets of paper are conventionally available in the form of folded sheets of either plastic or paper inserted into a binder spline. The binder spline is commonly an elongated member having a longitudinal slit opening for insertion of a cover and sheets of paper. The cover and paper sheets are held in place by friction. In this type of binder there is typically insufficient friction between the binder and the paper sheets to keep the paper sheets secured in the binder, especially when the cover folder is open. When these folders are opened, the paper sheets tend to slip from the binder if they are pulled with only a small amount of force.
Other prior art cover folders contain fasteners which must be inserted through the binder, cover, and sheets to hold the sheets securely to the folder. The use of such fasteners require that holes be made along the cover edge as well as along at least one edge of the inserted sheets. These holes are undesirable since the sheets tend to tear during normal handling causing the sheets to flip out of alignment with the binder. The use of such fasteners and punched holes in the sheets also detracts from the overall appearance of the cover folder.
Methods of binding sheets of paper in book form, of course, are known and have evolved over the years. These methods typically require the use of threads, staples and other sewing methods in conjunction with the application of glue to the binder in order to keep a number of pages bound in conventional book form. In view of the complexity of such methods, they are not intended for home or office use, but rather are employed by commercial binding manufacturers. There is the need, therefore, for a method that an individual user can employ in order to securely bind a small stack of paper sheets permanently and neatly to a cover folder without resorting to sewing, threading, or use of staples or metal fasteners.
U.S. Pat. No. 4,213,220 discloses a method for binding of books, magazines and the like which eliminates the use of thread, staples and other sewing methods. The method disclosed in this reference relies solely on gluing together individual sheets of paper in order to hold the individual sheets in a magazine or book-like form. In the described method a plurality of spaced notched cuts must first be made along the center fold line of each page to be bound. The notched cuts of each page are somewhat out of alignment so that when the pages are folded along a common fold line overlapping projections of each sheet of paper appear through the notched cuts. That is when the pages are folded along the common fold line, some portions (3) of paper remain visible and slightly project from all or some of the pages along the notched cuts.
When the spine of the book is glued, the glue adheres to each and every one of the spine edge of the pages especially in the projecting parts caused by the notched cuts. This improves the fixing or adhesion of the sheets one to another along the common fold line. It is evident that while eliminating the use of threads, staples and other sewing methods the described method is not designed for home or office use since the cuts or notches on each sheet of paper must be made precisely to a different level, from about 1/2 to 1 millimeter difference approximately. (Col. 1, lines 34-37.) In addition to the time-consuming step of making such notches, it cannot be reasonably expected that the user could make these cuts to such a fine tolerance without spreading a great deal of time and effort.
U.S. Pat. No. 2,455,971 describes improvements to the then conventional commercial book binding methods. This reference is characteristic of the complex commercial methods for binding sheets of paper in book form and it is evident that such methods involve a number of very precisely regulated steps. It is stated in the reference that the method described therein is expressly for the purpose of complete mechanization, in a continuous manner for the economical fabrication of books. (Col. 4, lines 13-16). This reference therefore is offered as an example of commercial, mechanized continuous book binding methods. It is evident that the method described in this reference involves a sequence of mechanized steps for cutting, aligning and gluing the individual paper sheets 28, together as at 29 and then subsequently glue the sheets to a strip of cotton crash 30. There are a number of steps involved in clamping and unclamping the sheets of paper and realigning the paper as glue is applied to the individual sheets and to the strip of cotton crash 30. The method described in this reference is clearly not intended for home or office use and in addition has the disadvantage that it requires an additional strip of cotton crash 30 to be glued to the individual sheets in order to firmly bind the paper sheets together in book form.
U.S. Pat. No. 1,765,194 discloses a tablet of loose-leaf forms which are bound with adhesive in such a manner that the tablet may be opened without destroying the grouping of the sheets and yet the tablet is designed so that any individual sheets can be readily removed by pulling on it. The individual sheets are bound together by adhesive 10a which is applied to an edge of the sheets aligned in a stepped manner as shown best in FIGS. 2 and 5. The alignment of sheets in stepped arrangement allows better adhesive contact between the underside of the adhesive portion of each sheet and the sheet below it. This strengthens the hinge between the sheets and therefore reduces the tendency of the sheets to come apart when the book is opened.
The method described in this patent is not practical for home or office use since the user must expend a considerable time in aligning the individual sheets in a stepped fashion before applying glue to the binding edge of the sheets. The user would typically also have to spend additional effort in binding a cover, for example, cover 14 after the individual sheets have been bound.
U.S. Pat. No. 4,486,032 discloses an improved cover folder with a binder spline which is designed to securely retain a cover and paper sheets inserted therein without the use of external fasteners or adhesive. This folder, while an improvement over cover folders in its class, is not intended as a permanent binder for sheets since the user can readily remove the sheets from the spline and insert a new set of sheets.
Accordingly, it is an object of the present invention to provide a cover folder which can be utilized to quickly and conveniently bind a small stack of paper sheets. A related object is to provide a binder spline which can be utilized to quickly and conveniently permanently bind a small stack of sheets.
Another object of the invention is to provide a method for conveniently binding a stack of sheets to a cover folder or a binder spline such that the sheets will not slip from the cover folder or binder when the sheets are spread open.